Which term represents a pair of contrasting characters?

Options

A. Homozygous
B. Heterozygous
C. Complementary genes
D. Allelomorphs

Answer

To solve the question "Which term represents a pair of contrasting characters?", we will analyze the options provided and understand the definitions of each term in relation to contrasting traits.

### Step-by-Step Solution:

1. **Understanding Contrasting Characters**:
- Contrasting characters refer to traits that are opposite in nature. For example, in pea plants studied by Mendel, the height can be either tall or dwarf. These two traits (tall and dwarf) are contrasting characters.

2. **Analyzing the Options**:
- **Homozygous**: This term refers to an organism that has two identical alleles for a particular trait (e.g., TT for tall or tt for dwarf). Since both alleles are the same, this does not represent contrasting characters.
- **Heterozygous**: This term refers to an organism that has two different alleles for a trait (e.g., Tt, where T is tall and t is dwarf). This condition indeed represents a pair of contrasting characters.
- **Complementary Genes**: This term refers to genes that work together to produce a particular trait but do not necessarily represent contrasting traits. Therefore, this option is incorrect.
- **Allelomorphs**: This term refers to different forms of a gene (alleles) that can exist in a population. While they can be contrasting, the term itself does not specifically denote a pair of contrasting characters.

3. **Conclusion**:
- After analyzing all the options, the term that best represents a pair of contrasting characters is **heterozygous** (option B).

### Final Answer:
The term that represents a pair of contrasting characters is **heterozygous**.

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